Lesson focus: Analysis turns measurements into a pattern that can answer the question.
Calculate a meanAn average found by adding up all the values and dividing by how many values there are., identify a pattern and choose a suitable graph.
Build on earlier learning
Recording dataRevisit the difference between raw and processed data before analysing a pattern.
You will be successful when you can…
- Calculate a mean from repeated measurements.
- Select bar charts or scatter graphs appropriately.
- Label axes, units and scales accurately.
- Describe patterns and anomalies without assuming causation.
Words that carry the science
- mean
- The sum of values divided by the number of values.
- bar chart
- A graph comparing separate categories using separated bars.
- scatter graph
- A graph plotting paired numerical values to examine a relationship.
- line of best fit
- A line or curve showing the overall trend rather than joining every point.
- correlation
- An association between two measured variables.
Turn results into a defensible pattern
01Summarise repeats honestly
Calculate a meanAn average found by adding up all the values and dividing by how many values there are. by adding the repeated values and dividing by their number. Show the raw data so variation remains visible.
Investigate an unexpected value before deciding whether exclusion is justified. Report any exclusion and, where possible, compare the conclusion with and without it.
02Choose the graph for the variable type
Use a bar chartA graph that uses separate bars to compare groups, such as the number of pupils who like each fruit. for separate categories such as material type. Use a scatter graphA graph of points that shows whether two sets of measurements are linked. when both variables are numerical, such as temperature and time.
In a controlled investigation, put the independent variable on the x-axis and dependent variable on the y-axis. Label quantity, unit and a sensible even scale.
03Describe before explaining
Describe direction, shape and exceptions: “as temperature increased from 20 to 50 °C, meanAn average found by adding up all the values and dividing by how many values there are. time decreased from 93 s to 45 s”. Use data to show scale.
correlationA link between two sets of measurements, where one tends to go up or down as the other changes. alone does not prove that one factor caused the other, especially in pattern-seeking studies with possible confounders.
Classify the independent variable before selecting the display.
- Separate categoriesbar chartA graph that uses separate bars to compare groups, such as the number of pupils who like each fruit.: material A, B and C; bars do not touch.
- Two numerical variablesscatter graphA graph of points that shows whether two sets of measurements are linked.: temperature and time; plot paired coordinates.
- Change over ordered timeline graphA graph where the points are joined by a line, used when both values are numbers, such as temperature over time. may show a continuous time series when connecting values is meaningful.
- Distribution of one variableA dot plot or histogram may be suitable later; retain the raw values now.
Line of best fit and an anomaly
A ball is dropped from different heights and its bounce is measured. Move the line until it passes as close as possible to the points, with about as many above as below. One result does not fit the pattern.
Controls
Results are illustrative. The anomaly (60 cm) is far below the line: repeat it rather than use it. Leaving it out moves the best line.
Calculate and describe
At 30 °C, dissolving times are 73 s, 75 s and 74 s.
- Add the values: 73 + 75 + 74 = 222 s.
- Divide by three: 222 ÷ 3 = 74 s.
- Compare with other temperature means rather than judging one row alone.
- Describe the overall direction and quote endpoints or representative values.
How to make the reasoning visible: A calculated value supports analysis only when the calculation and comparison are visible.
Choose and interpret
Use the table to decide the graph and write an evidence-based description.
| Temperature / °C | Mean dissolving time / s |
|---|---|
| 20 | 93 |
| 30 | 74 |
| 40 | 65.7 |
| 50 | 45 |
| 60 | 38 |
Graph skills: SLAPUK and choosing a scaleDrawing a graph of your results? Check it against SLAPUK.
Which type of graph should you draw for this data? Which variable goes on the x-axis (across the bottom)?
Describe the pattern. Use two numbers from the table.
Use the table to predict the mean dissolving time at 70 °C.
Check your understanding
Answer from memory, then check against the suggested answer.
How do you work out a mean?
When should you use a bar chart?
What does correlation mean?
When should you use a scatter graph or line graph?
What is a line of best fit?
One point on a graph is far away from the others. What should the student do?
Ice-cream sales and sunburn both go up in summer. Does ice cream cause sunburn? Explain.
Why should you describe a pattern before you explain it?
Exam Question Practice
Exam Question Practice
Mark points shown after marking
The mean reaction time is 84 s at 20 °C and 31 s at 50 °C. Describe the relationship. Use the data. Start: “As the temperature goes up, …”
(3)Total for this question: 3 marks
Command word: For describeA command word: say what happens or what something is like, step by step, without needing to give reasons., say what the data show. You do not need to explain why.